Employee service share based compensation recognized stock options.

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- Definition

Employee service share based compensation recognized stock options cancelled.

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Employee service share based compensation recognized stock options not met.

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- Definition

Share based compensation arrangement by share based payment award stock option grant date fair value.

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Aggregate number of common shares reserved for future issuance.

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Amount of cash inflow from exercise of option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Net number of share options (or share units) granted during the period.

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Gross number of share options (or share units) granted during the period.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Weighted average grant-date fair value of non-vested options forfeited.

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Number of share options (or share units) exercised during the current period.

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Stock-Based Compensation - Additional Information (Detail) - USD ($)		1 Months Ended			3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Jan. 01, 2020	Jul. 31, 2020	May 31, 2020	Apr. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jan. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense					$ 3,063,000	$ 1,550,000		$ 7,022,000	$ 4,480,000
Stock options exercised, shares								311,871	25,857
Proceeds from stock option exercises								$ 3,060,000	$ 178,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted to certain executives, consultants and employees								18,500
Shares, vesting period								4 years
Fair value of shares at grant date								194,000
Weighted average grant date fair value per share								$ 10.48
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance											1,085,619
2015 Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance					628,153			628,153
2007 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted to certain executives, consultants and employees								1,496,125
Options grant date fair value amount								$ 11,700,000
Weighted average grant date fair value of options								$ 7.82
Stock compensation expense		$ 1,000,000.0
Recognized compensation expense related to stock option not met								$ 0
Stock compensation expense								$ 180,000
Stock option not met, options cancelled	194,338						194,331
2007 Plan [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted to certain executives, consultants and employees				74,000						583,000
Recognized compensation expense related to stock option not met			$ 0
2007 Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period to recognize compensation expense								4 years
2007 Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period to recognize compensation expense								3 years
2015 and 2007 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period to recognize compensation expense								2 years 8 months 12 days
Unrecognized compensation expense related to stock option and RSUs					$ 15,500,000			$ 15,500,000